Flameholder construction



Feb. 22, 1955 w. G. TAYLOR, JR

mmm-roman CONSTRUCTION 2 Sheets-Sheet 1 Filedl sept. 25. 1951 NR. wm.

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NEN-VOR W|| L IAM GRANVILLE TAY L OR,JR.

Y B ATTORNEY QM Nh Feb. 22, V195s w. c. TAYLOR, JR

FLAMEHOLDER CONSTRUCTION 2 Sheets-Sheet 2 Filed Sept. 25. 1951 INV NTO WILLIAM GRAVILL TAYLOR JR;

AT 'TORNEY United States Patent O FLANIEHOLDER CONSTRUCTION William G. Taylor, Jr., Glastonbury, Count, assigner to United Aircraft Corporation, Et Hartford, Conn., a corporation of Delaware Application September 25, 1951, Serial No. 248,131

12 Claims. (CL 15o-35.6)

This invention relates to ameholders used, for example, in afterburners for jet engines or in other combustion chambers.

The ameholder functions to create enough turbulence in the gas flowing through the combustion chamber 1n which the ameholder is located to cause the combustible mixture to burn within the combustion chamber without having the ame blown downstream by the normal velocity of the gases through the chamber. Because of the temperature of the combustion taking place Within the chamber the ilameholder becomes extremely hotand has a relatively short life. A feature of this invention is an arrangement for supplying cooling air to the llameholder.

The arneholder elements are frequently supported on radially extending rods on which they are slidable to permit relative thermal expansion.to take place. One fea ture of this invention is an arrangement for cooling the supporting rods of the sldable connections for the llameholders in order to prevent the parts from binding during the operation of the combustion chamber 1n which the ilameholder is located.

When a device of this type is used in an afterburner i where combustion takes place only during a part of the jet engine operation, the necessity for cooling the ameholders exists only during afterburner operation. The afterburner is generally provided with a variable area nozzle which is opened when the afterburner is u ignited to provide a larger ow area at the discharge end of the combustion chamber. A feature of the invention is an arrangement by which the cooling air is circulated to the ilameholder only during the period that the variable area nozzle is full-open so that the cooling iluid is used only while the afterburner is in operation.

Other objects and advantages will be apparent from the specification and claims, and from the accompanying drawings which illustrate an embodiment of the inven tion.

Fig. l is a side elevation of an afterburner with the invention applied thereto.

Fig. 2 is a sectional view substantially along the hue 2-2 of Fig. l showing the flameholders and supports.

Fig. 3 is an enlarged fragmentary sectional View of a part of F ig. 2. f

Fig. 4 is a fragmentary sectional view of a part substantially along the line 4 4 of Fig. 2 showing the cooling air supply to the anieholders.

The invention is shown in an afterburner construction for use primarily in augmenting the thrust of a gas turbine power plant, the turbine exhaust of which is directed into the entrance 2 of the afterburner. The latter is in the form of a duct which has a portion 4 beginning at the admission end of the afterburner and gradually increasing in diameter to a point 6 approximately midway between the ends of the afterburner. Downstream of the point 6 the duct has a portion 8 which gradually decreases in diameter to the variable nozzle 10. Although the latter may be of any desired configuration, the arrangement shown is the eyelid type in which opposed eyelid members 12 (only one of which is shown) are pivoted on an axis 14 so that they may be moved apart to increase the nozzle area.

The eyelids are moved into open position hydraulically as, for example, by means of a cylinder 16 having a piston 18 therein with a projecting rod 29. The rod 20 is connected through a carriage 22 on a track 24 to a rod 26 extending to the eyelid. With this arrangement the Vand 36 connected respectively as by conduits 38 and 40 to the opposite ends of the cylinder 16. The valve casing 30 also has a discharge port 42 and the valve is so arranged thaethe outlet ports may be alternately connected to the inlet port 32 or to the discharge port.

Fuel is supplied to the combustion chamber by a fuel manifold 44 which surrounds the portion 4 of the duct and is connected to a number of radially extending fuel nozzles 46. lt will be understood that in operation the valve (not shown) which controls the supply of fuel to the nozzles may be interconnected with the valve 28 for controlling the eyelids. Downstream of the fuel nozzles are located tiameholders 48 and 50 which function to create suliicient turbulence so that the amewill not be blown downstream by the iiow of gas through the combustion chamber. Each of the ilameholders, as shown more clearly in Fig. 4, is substantially V-shaped in cross section with the base of the J projecting upstream and each ilamehclder is arranged in the form of a ring with the flameholder 50 positioned within the ring defined by the liameholder 48.

The ameholders are supported within the combustion chamber'by radially extending tubes 52 supported at their outer ends in bushings 54 carried by the duct portion 4 'and engaging at their inner ends in a cross-shaped member 56 in which the tubes may beslidable to accommodate differential thermal expansion. The tubes 52 pass through the ilameholders and the latter have sleeves 5S which surround and are slidable on the tubes. As best shown in Fig. 4, at each intersection of the ilameholder with any one of the tubes the ameholder carries a pair of relatively short sleeves 5S rather than a single long leevd'with these sleeves spaced apart as shown in Figs.

The tubes 52 are hollow, as shown, and the connecting member 56 is also hollow so that the tubes are interconnected for a ow of cooling liuid through all ofthe tubes. @ne of the tubes, the uppermost one in the arrangement shownvin Fig. 2, has a fitting 60 connected thereto for a supply of cooling air into the tube. The remaining tubes have their outer ends plugged as at 62 (Fig. 3) and are held in position within the supporting bushings 54 by a transverse pin 64. With this arrangement cooling fluid under pressure is supplied to all of the tubes and is allowed to escape from the tubes into the ameholders through openings 66 in the tubes. These openings are located between the opposed sleeve 58 carried by the ameholders. To assure a more uniform distribution of the cooling uid escaping through the opening 66, the pair of sleeves 58 is surrounded by an overlying sleeve 63 in such a manner that the cooling air is caused to blow out in a direction substantially parallel to the supporting tubes and into the V-shaped conguration of the ameholder. This cooling fluid also functions to cool the tubes as will be apparent anda small portion of the cooling fluid may leak out between the tube and the surrounding sleeves 58.

In order to supply cooling fluid only while the afterburner is in operation the littingll is connected by a tube 70 having a check valve 72 therein to the duct 40 leading to the downstream end of the eyelid actuating cylinder. As above stated, when the afterburner is in operation the eyelids are opened by the admission of uid under pressure to the downstream end of the cylinder 16. Accordingly, at the same time, the fluid under pressure will pass through duct 70 of the fitting 60 into the intersecting tubes 52 and thence to the llameholders. The check valve 72 is arranged as shown in Fig. 4 to prevent the back ow of gas from the afterburner duct into the actuating mechanism when pressure is not applied to the downstream end of the actuating cylinder.

Although the device has been described in conjunction with an afterburner for use on a gas turbine power plant,

' plicable for other combustion cham Y of the rate of tiow of gas through the combustion chamla nozzle area increasing means located .in the ductadjacentto and downstream it `will be vunderstood that the arrangiment 'is A y ber duct it becomes necessary to create more or less turbulencein order to. rmit combustion to take'place.

' It is tov be underst Vto the specic embodiment herein illustrated andvde# scribed, but may be used in'other ways without departure fromlr its spirit as defined by the following claims.

v'Icaim: Y- Y 1. A burner in the form of a duct'havinga variable area -nozzle at its vdownstream end, means for varying the area of the nozzle, means for supplying fuel to the,`

duct upstream of the nozzle, tlameho1ders si ibstantially in the form of open V-shaped members within the duct Y downstream of thevfuel supplying means, tubularineans forV supporting 4saicl ameholders, means for supplying a f cooling ,fluid to said tubular means and thence :to the ameholders, and means responsive to actuation ofA-said nozzle .varying means for controlling said cooling uid supplying means. t Q

25A burner in the form of a duct having a variable area. nozzle at'its downstream end, means for varying the area of the nozzle, tlameholders within the duct, radially Y extending tubes supported by the duct at their outer ends v and operating `to support the flameholders in position.

within the duct, means for supplying cooling uid through said tubes to the Vilameholders and means responsive to` actuation of said nozzle varying means forcontrolling the admission ,of cooling uid from said supplying means to said supporting tubes and thence to the ilameholders.

3. A burnerin the form of a. duct havinga variable l area nozzle at its downstream end, means for varying theV area ofthe nozzle, flameholderswithin the duct; radially extendingtubes supported by the duct at their 'outer ends and, operating to support the ameholders in position the'duct, 'and means responsive to actuation of said nozzle varying means for admitting cooling tluid to -said supporting tubes andthence to the llamholdersaid tubesbeing hollow and having passages therein adjacent to the tiamjeholders for the-escape of the cooling uid fromA the tubes into the ilameholders.

4. An afterburuer construction in the form of a diict. linto which the turbine exhaust gas is directed, said duct having an upstream portion gradually increasing in diameter in the direction'of gas ow throughv the duct, said duct having a variable yarea thrust nozzle at its downstream end, reversible iluid pressure actuated means for 'varying `the area of the nozzle and means for admitting uid under pressureto said pressure actuated means in on, in combination with of the inlet end and in rsaid upstream portion for supplying fuel to said duct, ameholders linthe duct downstream of Athe fuelsupplyingl means and also located in said .upstream portion and a connectionfor delivering fluid under pressure from said iluid pressure actuated means to said llameholder when liuid is admitted by said iluid admitting means in a nonlekk area increasing direction.

5. A `combustion chamber including, a duct throu which gas Itiows andv into which fuelV is injected to" burned with the gas, ilameholders in the form of rings located in said duct, transversely extending intersecting tubes-supporting said ameholders, means for introducing coolingtluid intolsaid tubes, and passages through l I 1. Afmbusaoa chamber including.. am@

rs where y reason vthat the invention is notilimited` k being substantially ,aV-shaped .in cross section-wi l base of the y rojecting upstream, transversely extending supporting :said iiameholders, said .tiameholders on said tubes toprovide for diierential" lwhich gas owsand into located in said duct, transversely extending intersecting tubes supportinglsaid tlameholders, said liameholders Q being slidable onsaid tubes to provide for dierential expansion, means for introducingfcooling duid to said V tubes, and passages through said tubes-and into said ilameholders for the escape? of the coolinguid from'V the tubes into the ameholders, said llameholders ha 10 sleeves` thereon surroundingjthesupporting tubes slidable thereon. I n y 8. A `combustion chamber including a duct ththe intersecting tu supporting said ameholdersfeach leg of the v of the ilameholder having a sleeve thereoli fthrough which the tubes'l extend and are slidable,\radial passages in said tubes between the' adjacent ends of the i tubesand within the V-shaped cross `section of the dameholdei' for theescape of the coo lluidfrom the'tubes or supplying ber in'ciudmg 's am ,M Y

into the flameholder, and' means tluid under pressure to said tubes.

9. A combustion .c h which gas flows and in whichfuel is burned with the gas, ameholders located in said duct, said ameholders being substantially V-shaped'gincross section with the base of the V projecting upstream, transversely'extending intersecting tubes supporting said vtlameholders, thelatterhav` ing sleeves thereon through whichthe tubes extend and are slidable, means for supplying cooling fluid-to said tubes, radialpassages in said vtubes located between adjacent supporting sleeves for the escape of the cooling duid f `Vfrom the tubes into the ilaineholder..

" 10.l A combustion chamber including a duct through which gas ows a'nd in which fuel is burned with the gas,

flameholders located'in said duct, said flameholders'being substantially V-shaped in cross section with the base of the V projecting upstream, transverselyextending intersecting:

tubesvsu'pporting l said ameholders, the latter having sleeves thereon through which the tubes extend and are.,

slidable, means for supplying cooling iluid to lsaid tubes, radial passages in said tubes located between adiacent supporting sleeves for the escape of cooling uid from the 'tubes into the ameholdei', and a sleeve on the tube overlying'the passages and extending `between the-adjacent supporting sleeves forfdirecting the llow of cooling fluid.

o 1l. In an afterburner, a'duct through which gas from,

a gas turbine is'directed ito a thrust nozzle. ameholders positioned within said duct, radially `extending tubes positioned within said, duct and supporting said flameholders, the llatter 'having sleeves therein through whichV the tubes extend and are` slidable, means for supplying cooling tluid to certain tubes, and passages in said'certain tubes adjacent to the sleeves for introducing `the cooling uid from said tubes into the aineholders.

'12. In an afterburner, a duct through which gas from a gas turbine is directed to a thrust nozzle. ameholders tioned within said duct andvsupporting said vameholders, the latter having sleeves therein through which the tubes extend, means for supplying cooling fluid to certain tubes, u 4and means for introducing cooling uid from said tubes into the tiameholders, said last means including radially extending passagesr in said tubes and a sleeve surround `ing the .tube and overlying said` passages to cause the tlow of cooling uid into the ilameholdersin a direction substantially parallel to the tubes. f

V,References Cldfin the iile of this paienty v UNITED STATES PATENTS 2,479,573

Howard Aug. 23, 1949 2,508,420 Redding -May 23, 1950 2,551,229 1 Alford etal. v May 1, 1951 2,552,492 NathanY May-8, 1951 2,565,854 Johnstone etal. Aug.y 28, 1951 Y 2592060 ulianot Apr. 8, 1952 215961435` Reben May 13,1952

wiiiciif'ue'i ainecied m iy burned with the gas, ameholdersin the form of which gas -ows and` in which `fuel is burned with gas, tlameholderslocated in said duct, said ilameholders x positioned within said duct, radially extending tubes posi- 

